Recarbrio is a three-drug combination injection made up of the FDA-approved antibiotic – imipenem/cilastatin, and a new beta-lactamase inhibitor – relebactam.

While imipenem is a penem antibacterial drug, cilastatin sodium is a renal dehydropeptidase inhibitor. Cilastatin, which does not have antibacterial activity, restricts the renal metabolism of imipenem.

Imipenem’s bactericidal activity comes from its binding to PBP 2 and PBP 1B in Enterobacteriaceae and Pseudomonas aeruginosa and the following inhibition of penicillin-binding proteins (PBPs). Blocking of PBPs results in the disruption of bacterial cell wall synthesis.

Recarbrio FDA approval was based on the efficacy determination of the drug, which was supported partly by the findings of the efficacy and safety of imipenem-cilastatin for the treatment of complicated urinary tract infections and complicated intra-abdominal infections.

Relebactam’s contribution to Recarbrio was evaluated based on results from in vitro studies and animal models of infection. Recarbrio’s safety when administered through injection, was assessed in a couple of trials, one each for the two targeted indications.

Commenting on Recarbrio FDA approval, Ed Cox – director for the Office of Antimicrobial Products in FDA Center for Drug Evaluation and Research, said: “The FDA remains focused on facilitating the development of safe and effective new antibacterial drugs to give patients more options to fight serious infections.

“It is important that the use of Recarbrio be reserved for situations when there are limited or no alternative antibacterial drugs for treating a patient’s infection.”

Merck expects to launch Recarbrio later this year.

Dr. Nick Kartsonis – senior vice president, infectious diseases and vaccines at Merck Research Laboratories, commenting on Recarbrio FDA approval, said: “Today’s announcement is a great example of Merck’s longstanding commitment to infectious diseases research and development, as we continue to search for novel ways to approach difficult-to-treat pathogens.”